problem
The Number Jumbler
Age
7 to 14
Challenge level
The Number Jumbler can always work out your chosen symbol. Can you work out how?
problem
Your number is...
Age
7 to 14
Challenge level
Think of a number and follow the machine's instructions... I know what your number is! Can you explain how I know?
problem
Special Numbers
Age
11 to 14
Challenge level
My two digit number is special because adding the sum of its digits to the product of its digits gives me my original number. What could my number be?
problem
Number Pyramids
Age
11 to 14
Challenge level
Try entering different sets of numbers in the number pyramids. How does the total at the top change?
problem
Crossed Ends
Age
11 to 14
Challenge level
Crosses can be drawn on number grids of various sizes. What do you notice when you add opposite ends?
problem
Perimeter Expressions
Age
11 to 14
Challenge level
Create some shapes by combining two or more rectangles. What can you say about the areas and perimeters of the shapes you can make?
problem
The Simple Life
Age
11 to 14
Challenge level
The answer is $5x+8y$... What was the question?
problem
Think of Two Numbers
Age
11 to 14
Challenge level
Think of two whole numbers under 10, and follow the steps. I can work out both your numbers very quickly. How?
problem
More Number Pyramids
Age
11 to 14
Challenge level
When number pyramids have a sequence on the bottom layer, some interesting patterns emerge...
problem
Always a multiple?
Age
11 to 14
Challenge level
Think of a two digit number, reverse the digits, and add the numbers together. Something special happens...
problem
Quadratic Patterns
Age
11 to 14
Challenge level
Surprising numerical patterns can be explained using algebra and diagrams...
problem
Reversals
Age
11 to 14
Challenge level
Where should you start, if you want to finish back where you started?
problem
Fibonacci Surprises
Age
11 to 14
Challenge level
Play around with the Fibonacci sequence and discover some surprising results!
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You may also be interested in this collection of activities from the STEM Learning website, that complement the NRICH activities above.